This disclosure relates to a seal provided between a shaft and a housing of an air cycle machine.
An air cycle machine may include a centrifugal compressor and a centrifugal turbine mounted for co-rotation on a shaft within a housing. The centrifugal compressor further compresses partially compressed air, such as bleed air received from a compressor of a gas turbine engine. The compressed air discharges to a downstream heat exchanger or other use before returning to the centrifugal turbine. The compressed air expands in the turbine to thereby drive the compressor. The air output from the turbine may be utilized as an air supply for a vehicle, such as the cabin of an aircraft.
The shaft is rotationally supported by air bearings within the housing. A variety of seals are used between the shaft and the housing to seal the shaft relative to the housing. Some prior seals have an outer diameter/length/width of 3.460/0.685/0.16 inch (87.88/17.40/4.1 mm), 2.706/0.370/0.21 inch (68.73/9.40/5.3 mm) or 1.875/0.455/0.14 inch (47.63/11.30/3.6 mm).